Substituted cinnanyl thiocyanates and their isomers

ABSTRACT

COMPOUNDS CORRESPONDING OF THE FORMULA   ARYL-C(-R)=C(-R1)-CH(-R2)-Y   WHEREIN ARYL IS PHENYL, SUBSTITUTED PHENYL, NAPHTHYL, AND SUBSTITUTED NAPHTHYL IN WHICH THE SUBSTITUENTS ARE HALOGEN, NITRO, AND LOWER ALKYL; R IS INDEPENDENTLY HYDROGEN, OR LOWER ALKYL; R1 IS INDEPENDENTLY HYDROGEN, LOWER ALKYL, OR PHENYL; R2 IS INDEPENDENTLY HYDROGEN, LOWER ALKYL, AND PHENYL; WITH THE PROVISION THAT R, R1, AND R2 ARE NOT SIMULTANEOUSLY HYDROGEN WHEN ARYL IS PHENYL; AND Y IS SELECTED FROM THE GROUP CONSISTING OF -SCN AND -NCS. THE ABOVE-DEFINED COMPOUNDS ARE EFFECTIVE HERBICIDES.

United States Patent 3,749,747 SUBSTITUTED CINNANYL THIOCYANATES AND THEIR ISOMERS Llewellyn W. Fancher, Orinda, Califi, assignor to Stautfer Chemical Company, New York, ELY. N0 Drawing. Filed May 12, 1970, Ser. No. 36,701 Int. Cl. C07c 161/02, 161/04 US. Cl. 260-454 4 Claims ABSTRACT OF THE DISCLOSUIUE Compounds corresponding to the formula R R R, ARYLJJ=C HY wherein ARYL is phenyl, substituted phenyl, naphthyl, and substituted naphthyl in which the substituents are halogen, nitro, and lower alkyl; R is independently hydrogen, or lower alkyl; R is independently hydrogen, lower alkyl, or phenyl; R is independently hydrogen, lower alkyl, and phenyl; with the provision that R, R and R are not simultaneously hydrogen when ARYL is phenyl; and Y is selected from the group consisting of fiSCN and NCS. The above-defined compounds are eifective herbicides.

SUMMARY OF THE INVENTION The invention relates to certain new compounds and their utility as active herbicidal substances. In particular, this invention pertains to certain novel materials having the general formula:

in which ARYL is selected from the group consisting of phenyl, naphthyl, substituted phenyl and substituted naphthyl in which the substituents are selected from the group consisting of halogen, nitro, and lower alkyl; R is selected from the group consisting of hydrogen and lower alkyl; R is selected from the group consisting of hydrogen, lower alkyl and phenyl; and R is selected from the group consisting of hydrogen, lower alkyl, and phenyl; with the provision and R, R and R are not simultaneously hydrogen when ARYL is phenyl; and Y is selected from the group consisting of SCN and NCS, and the use of these materials as herbicides.

Preferably, the compounds of the invention have the formula Xm Zn R1 R2 R3 Quanta...

wherein X is selected from the group consisting of Cl, Br, and I; m is a whole number from 0 to 3; Z is NO n is a whole number from 0 to 2; R is selected from the group consisting of hydrogen and alkyl containing 1 through 5 carbon atoms; R is selected from the group consisting of hydrogen and alkyl containing 1 through 5 carbon atoms; R is selected from the group consisting of hydrogen and alkyl containing 1 through 5 carbon atoms and phenyl, with the provision that R R and R are not simultaneously hydrogen, when n and m are both zero; and Y is selected from the group consisting of SCN and NCS. In its most preferred form, the invention concerns compounds having the formula @ijiii...

wherein X is selected from the group consisting of Cl, Br, and I; m is a whole number from 0 to 2; R is selected from the group consisting of hydrogen, methyl, and ethyl; R is selected from the group consisting of hydrogen, methyl, and ethyl; R is selected from the group consisting of hydrogen, methyl, ethyl, and phenyl; with the provision that R R and R are not simultaneously hydrogen, when m is zero; and Y is selected from the group consisting of SCN and NCS; and the use of these compounds as herbicides.

The present invention also includes, as indicated, a method of controlling undesirable plants which comprises applying an effective amount of the above-described compounds to the plant or to a locus to be controlled or protected.

The compounds of the invention may be prepared by the following general reactions:

ARYL(|3=(]JJ)HNOS NaCl wherein ARYL, R, R and R are as above indicated.

The intermediate cinnamyl-type alcohols are easily prepared according to the method taught in US. Pat. No. 3,094,561. This method comprises generally the condensation of an appropriate arylaldehyde with acetaldehyde or other suitable aldehyde in the presence of potassium hydroxide an ethanol to yield a cinnamaldehyde-type compound. This aldehyde is then reduced with a reducing agent such as aluminum isopropoxide to form the cinnamyly alcohol type compound.

In general, lower temperature appear to favor reaction (2), while higher temperature appear to favor reaction (3). In some instances, as will be readily appreciated by those of skill in the art, mixtures will be obtained. Temperatures of reaction which favor the thiocyanate would appear to be in the range of about 5 C. to 25 C. while temperatures of from about 60 C. to C. tend to favor the isothiocyanate. Where mixtures of product are obtained, they are readily separated by techniques known to those skilled in the art.

The reactions are preferably carried out in the liquid phase. The employment of a solvent is useful in facilitating processing as well as agitation of the reactants. Suit 3 able solvents are benzene, chlorobenzene, toluene and the like.

As a consequence of the special geometry of the carbon-carbon double bond and restricted rotation about this bond, the possibility exists in the compounds of the present invention of geometric isomerism. Cis-trans isomerism is -very frequently encountered in this type of structure containing a carbon-carbon double bond. It is recognized that the trans isomers are usually more stable than the corresponding cis isomers. The existence of both stereoisomeric forms is believed to exist for the majority of the compounds described herein. Thus, the compounds of the present invention are not limited to any specific geometric isomer configuration. The physical properties of cis and trans isomers are usually quite similar, and separation of both from a mixture by techniques such as fractional distillation or crystallization is not always possible.

In order to demonstrate the preparation of the compounds of the invention, the following examples are provided.

EXAMPLE 1 Preparation of 1,3-diphenyl-3-chloro-propene-1 Approximately 21 grams (0.1 M) of 1,3-diphenyl-3- hydroxy-propene-l are dissolved in 40 cc. of CHCl and 1.0 gram of triethylamine hydrochloride is added. About 13.1 grams (.11 M) of SOCl in ml. of CHCl are then added, with stirring, over a 15 minute period. The temperature is maintained between C. and C. After stirring an additional hour, the reaction mixture is allowed to stand for about 12 hours. The mixture is then purged with air to remove HCl and SOCI About 100 ml. of benzene is added, and the mixture is washed, until basic, with NaI-ICO and then washed with H O. The product is then dried over MgSO evaporated to give 1,3-diphenyl-3-chloro-propene-1. N =1.6110.

EXAMPLE 2 Preparation of 1,3-diphenyl-3-isothiocyanate-propene-1 About 19.9 grams (0.08 M) of 1,3-diphenyl-3-chloropropene-l, 100 ml. of acetone, and 10.5 g. (0.13 M) of NaSCN are mixed and refluxed for about an hour at a temperature of about 60 C. The reaction mixture is then evaporated to one-half volume, poured into cold water, and extracted with benzene. The extractant is then dried with MgSO filtered, and evaporated with air on a steam bath to produce 1,3-diphenyl-3-isothiocyanate-propene-1. N =1.6315.

EXAMPLE 3 Preparation of l-phenyl-2-methyl-3-thiocyanatopropene-1 The procedure is similar to that of Example 2, except that l-phenyl-2-methyl-3-chloro-propene-1 is employed instead of the l,3-diphenyl-3-chloro-propene-1, the temperature at initiation is less than 10 C., and the mixture is stirred for three hours at less than 5 C. A good yield of 1-phenyl-2-methyl-3-thiocyanato-propene-1 is obtained. N =1.5635.

EXAMPLE 4 Preparation of l-(p-chlorophenyl)-2-methyl-3-thiocyanato-propene-l The procedure is similar to that of Example 3, except that l-pchlorophenyl-2-methyl 3 chloro propene 1 is employed instead of 1 phenyl 2 methyl 3 chloropropene-1.

EXAMPLE 5 Preparation of 1-(2,4-dichlorophenyl)-3-thiocyanatopro pene- 1 The procedure is similar to that of Example 3, except that 1-(2,4-dichlorophenyl)-3 chloro-propene 1 is em- 4 ployed instead of 1-phenyl-2-methyl-3-chloro-propene 1. M.P. C.88 C.

EXAMPLE 6 Preparation of l-(2-chlorophenyl)-3-isothiocyanatopropene-1 The procedure is similar to that of Example 2, except that 1-(2-chlorophenyl)-3-chloro-propene-1 is employed instead of 1,3-diphenyl-3-chloro-propene-1. N =1.6098.

EXAMPLE 7 Preparation of 1-1-naphthyl-3-methyl-3-thiocyanato propene-1 The procedure is similar to that of Example 3, except that l-l-naphthyl-S-methyl 3 chloro propene is employed instead of 1-phenyl-2-methyl-3-chloro-propene-1.

EXAMPLE 8 Preparation of l-(2-nitrophenyl)3-isocyanato-propene-1 The procedure employed is similar to that in Example 2, except that 1-(2-nitrophenyl)-3-chloro-propene-1 is employed instead of the 1,3-diphenyl-3-chloro-propene-1.

Compounds which may be produced according to the invention include:

As previously indicated, the compositions of the invention are phytotoxic compounds which are useful and valuable in controlling various plant species. The compounds designated as 3, 5, and 15 in the table were tested as heribicides in the following manner.

Seeds of four species including crabgrass, mustard, curled dock, and one crop pinto beans (Phaseolus vulgaris) are planted about one-half inch deep in sandy loam soil in individual rows in flats. Enough seeds are planted to give 30 to 50 plants of each species per fiat, and the flats are Watered after planting. The flats are placed in the greenhouse at 50 to 85 F. and watered daily with a sprinkler. About 10 to 14 days after planting when the primary leaves of the bean plant are almost fully expanded and the first trifoliate leaves are just starting to form, the plants are sprayed. The spray is prepared by weighing out about 50 mg. of the test compound, dissolving it in 15 ml. of acetone containing about 1 percent Tween (polyoxyethylene monolaurate), and then adding 5 ml. of water. The solution is sprayed on the foliage using an atomizer. The spray concentration is about 0.5% and the rate would be approximately 20 1b./ acre if all of the spray was retained on the plant and soil. However, since some spray is lost, it is estimated that the actual application rate is approximately 12.5 lb./acre.

The treated plants are placed back in the greenhouse and care is taken to avoid sprinkling the treated foliage with water for three days after treatment. Water is applied to the soil by means of a slow stream from watering hose. Injury rates are recorded 14 days after treatment. A rating of 0 to 10 is given based on estimated injury'or kill. The results of this test are reported in Table II.

TABLE II Rate 201bs./aere Crabgress Mustard Curled dock Pinto bean Compound (Dtgiiaris (Brassicu (Rumex (Phaseolus number sanguinalis) juncea) crispus) vulgaris) As can be seen by the test results, the compounds of the invention are useful as herbicides. The compounds may be applied directly to the particular undesired plant species or may be applied to a locus to be protected. In either event, it is, of course, necessary that the unwanted species receive an effective dosage of amount, i.e., an amount sufficient to kill or retard growth.

The compounds are normally employed with a suitable carrier and may be applied as a dust, spray, drench or aerosol. The compounds thus may be applied in combination with solvents, diluents, various surface active agents (for example, detergents, soaps, or other emulsifying or wetting agents, surface active clays) carrier media, adhesives, spreading agents, humectants, and the like. They may also be combined with other biologically active compositions, including other herbicides, fungicides, bactericides, and algaccides, insecticides, growth stimulators, acaricides, molluscicides, etc., as well as with fertilizers, soil modifiers, etc. The compounds of the invention may be used in combination with an inert carrier and a surface active or emulsifying agent and may also be applied in combination with other biologically active materials, in conjunction with a carrier and a surface active or emulsifying agent. The solid and liquid formulations can be prepared by any of the conventional methods wellknown to those skilled in the art. Determination of the optimum effective concentration for a specific application is readily conducted by routine procedures, as will be apparent to those skilled in the art. As indicated, the amount applied in a given case will be an eifective amount,

i.e., an amount sufiicient to give the type of control desired.

What is claimed is:

1. A compound having the formula wherein X is selected from the group consisting of Cl, Br, and I; m is a whole number from 0 to 2; R is selected from the group consisting of hydrogen, methyl, and ethyl; R is selected from the group consisting of hydrogen, methyl, and ethyl; R is selected from the group consisting of hydrogen, methyl, ethyl, and phenyl, with the provision that R R and R are not simultaneously hydrogen when m is zero; and Y is selected from the group consisting of SCN and NCS.

2. The compound of claim 1 wherein m is 0, R is hydrogen, R is methyl, R is hydrogen, and Y is -SCN.

3. 1-(2-chlorophenyl)-3-thiocyanato-propene-1.

4. 1-(2,4-dichloropheny1)3isothiocyanato-propene-l.

References Cited UNITED STATES PATENTS OTHER REFERENCES Smith et al.: The Isomerization of alkyl thiocyanates, etc. (1960), JACS 82, pp. 3076-82 (1960).

Dombrovskii et al. Haloarylation of usat. compds., etc. (1956), CA 51, p. 7337 (1957).

ELBERT L. ROBERTS, Primary Examiner G. HOLLRAH, Assistant Examiner US. Cl. X.R. 71-104 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- ,7 ,7 Dated July 31, 1973 Inventor(s) Llewellyn ncher It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 49, "potassium hydroxide and ethanol" should read potassium hydroxide and ethanol line 53, "to form the cinnamyly alcohol" should read to form the cinnamyl alcohol Column 3, line 6, "Cisftrans isomerism" should read Cis-trans isomerism line 9, "trans isomers" should read trans isomer: 'l'llie 10, "(:15 isomers" should read 'cis isomers line 15, C15 and trans isomers" should I read (:15 and trans isomers Column 4, line 73, the portion of the lifieireading by means of a slow stream from watering" should read by means of a slow stream from a watering Signed and sealed this 24th day of September 1974.

(SEAL) :Attest:

MCCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents F ORM PO-105O (10-69) UBCOMM-DC 60376-P69 vr n.5 GOVERNMENT PRINTING OFFICE: Isis o-ss6-asl, 

